Cathead construction



22, 1940- D. 1.. BUTLER GATHEAD CONSTRUCTION Filed March 28, 1938 flarzz'e/ L. But/er @TOBNE Y S Patented a. 22, 1940 UNITED STATES PATENT OFFICE I 2,218,742 I GATHEAD CONSTRUCTION Daniel L. Butler, Rodessa, La.

Application March 28, 1938, Serial No. 198,382

1 Claim.

- This invention relates to a cathead construction such as usedon drawworks, or hoists. It is the presentpractice to secure catheads to the shafts by means of a tight tapered key. From time to time the catheads must be removed for repairs, or when they are worn out, and considerable difficulty is occasioned in removing them from their shafts. One of the reasons for this difficulty is that there is very little space between the inner end of the cathead and the adjacent end of the cathead frame.

The general object of this invention is to provide a cathead construction which will overcome this difficulty, and which will provide a simple construction enabling the worn part of the cathead to be readily removed when necessary.

In accordance with the invention, the cathead the cathead. Usually the wear at the inner head will be considerably greater than at the outer head, due to the fact that the line from a cathead generally runs in toward the axis of the well. With an ordinary cathead construction this wear necessitates repair work to be done on the cathead from time to time. One of the objects of .this invention is to provide a construction whereby the cathead spool can be readily removed and applied in a reverse position so as to bring the wear on the other end of the spool. In

this way the life of the cathead without requiring repair, can be substantially doubled.

On account of the wear of the cathead spool,

it would be advantageous to have the spool of very hard wear-resisting material, but as catheads are usually made inone piece, this would cathead construction.

Fig. 1 is a vertical section through a cathead 6 embodying myinvention, and showing an ading connection between the shaft and the hubof the cathead body.

Fig. 3 is a cross-section taken about on the line 33 of- Fig. 1, and illustrating the loose key conmotion between the spool and the neck of the cathead.

In practicing the invention, I provide a cathead body I, which is made of ordinary steel, and provided with an integral hub 2 at one end. This body I preferably extends considerably beyond the end of the jack shaft 3 to which the cathead is attached. The cathead body is attached to the jack shaft with the usual type of tapered key 4 driven into aligning key seats or slots 5 in the hub, and in the shaft.

The inner end of the hub 2 is located quite close to the endface of the frame of the drawworks', which supports the jack shaft 3, and the position of this end face is indicated by the line 6 in Fig. 1. The projecting portion of the cat head body I is formed with a neck 1 of reduced diameter, and on this neck I provide a spool 8 in the form of a sleeve with slightly enlarged heads 9 at its ends. The inner face of this spool and the outer face of the neck 1 have grooves l0 cut therein to receive a straight key ll that is to say, a key that is untapered and is not tight in the slots. In other words, it is simply a driving key for transmitting motion'through the body I to the'spool. By reason of the reduced neck I an annular shoulder 12 is formed at the inner end of the neck, and against this shoulder the inner end of the spool 8 seats. I prefer to form this end of the spool with a counterbore I3 of the same diameter as the body 1 adjacent the shoulder l2. In other words, the shoulder is countersunk into the end of the spool.

In order to retain the spool and at the same time to enable it to be readily removable when desired, and also reversible, I provide the outerend of the spool with a counterbore [4, which is preferably of the same diameter and depth as the counterbore [3. And I provide a follower I5, which may be in the form of a ring, but is illustrated in the form of a plate l5, which fits into the counterbore I4. Suitable means is provided for securing this follower to the end of the body I, and this preferably consists of a plurality of circumferentially disposed fasteners, such as machine screws IG, which are threaded in openings spaced circumferentially around the wall of the body. With this arrangement it will be evident that the shoulder 12 and the edge of the follower l5, will resist any end thrust on the spool incidental to winding on or taking off a line from the spool. ably worn, and eventually must be built up when they become too worn to function properly; or else a new cathead spool must be substituted. When the spool becomes worn it can be readily removed by removing the follower l5, slipping the spool off, and replacing it in a reversed position When this is done, of course, the counterbore l4 fits over the shoulder l2, and the follower l5 fits into the counterbore IS. The spool 8 is preferably made of hardened steel, to enable it to resist wear. is quite thin, the amount of metal in it is quite small. A relatively long-lived cathead results, which is of Very slightly more cost to construct than an ordinary cathead. 7

One of the advantages of my construction is that I avoid any large projecting part on the end of the cathead spool. Such a projecting part is very objectionable because there is danger of a line becoming fouled by it. Accidents could happen from this cause.

In time, the heads 9 become consider- And as the shell of the spool By reason of the fact that the member that retains the spool 8 is not threaded so that it will screw onto the end of the neck 1, my construction has the advantage that the turning of the spool in either direction cannot loosen the cathead. Furthermore by providing a great number of relatively small fastening devices disposed circumferentially, very small fastening devices or bolts can be employed which do not present any substantial obstruction on the outer face of the follower l5 even if they are not countersunk. This results in a very serviceable construction which can be very economically built.

What I claim is:

In a cathead construction for draw-works or the like, the combination of a shaft, a cathead having a hubrigidly secured to the shaft and having an enlarged tubular body projecting beyond the end of the shaft, said body having a neck of reduced diameter toward its outer end and having an annular shoulder adjacent its inner end, a cathead spool received on the said neck, having a counterbore on its inner end receiving the said shoulder, a loose straight keyand-slot connection between the neck and the spool permitting the spool to be readily removed for repair, the outer end of said spool having a counterbore of the same diameter as the firstnamed counterbore, a follower plate set into the end of said cathead spool and received in said last-named counterbore, with its outer face flush with the end of the spool, said counterbores 00- operating to enable the spool to be removed and applied against the said shoulder in a reversed position.

DANIEL L. BUTLER. 

